Aha, acceptance! The patient is making progress.
Well actually it's the public's decision that matters. (Most) voters know that referendum or election campaign promises by either/all sides are not made under oath, and we have no way of knowing how much or how little credence voters gave to any particular claim in reaching their decision. Indeed, if Remain had won, I could not prove one way or another whether George Osborne's emergency budget threat had swung it.
Of course, the irony is that we still haven't even left yet, so none of us knows for certain which forecasts of glory or doom will come ultimately to pass. We know that there has been economic turbulence in the past two years around the ongoing uncertainty about whether, when and how the public's decision will be implemented, but people could blame that on the Theresa May government's shoddy negotiating or the Remainers' ongoing delaying tactics, depending on their perspective.
If Jeremy Corbyn gets his way at the next General Election, we might yet have the chance to test that out, or at least some very similar "promises"!